1. Field of the Invention.
The present invention relates to an underwater illumination system. More particularly, the present invention relates to a waterproof fitting for a light conduit illumination system, for providing safe light in swimming pools, spas, and other applications where electricity creates dangers due to the presence of water.
2. The Prior Art
In underwater applications, such as illuminating swimming pools, typically a recess is formed in the side wall of a swimming pool below the water line. A small diameter tunnel, large enough to accommodate a conduit, which carries power lines, is formed from the recess to a point about one foot above the surface of the ground. An incandescent lamp seated in a housing is placed within the recess, and the conduit is inserted through the tunnel and fixed to the housing. Electrical power lines run from a source of power through the conduit and to the lamp. A collar may be placed over the face of the lamp housing inside the pool, to present a pleasant appearance.
The apparatus is not waterproof. Rather, water surrounds the housing that holds lamp, enters the conduit, and surrounds the power lines within the conduit. Naturally, the water reaches the same level within the tunnel as it reaches within the pool or spa. Thus, the housing, conduit, and power line is continually bathed in water. Because the lamp is confined within a small recess, it would overheat and burn out prematurely if the lamp housing were not continuously bathed in water. The water circulates because convection causes the heated water within the recess to be is laced by cooler water.
Even if the housing and conduit were waterproof, it must be expected that water will enter the conduit tunnel and settle in low spots in the tunnel. Rain water and water used to wash the area around the pool often falls on the ground level access side of the lighting system and flows into the tunnel.
Burrs form whenever metal conduit is cut. Building codes require that cut and formed conduit be de-burred prior to installation of electrical wiring, but this requirement is often ignored. When the electrical power line is pulled through the conduit during installation of the system, the insulation may be abraded or stripped, leading either to premature failure of the insulation, or a source of leakage current from the time of installation.
In addition, continual exposure to water and the chemicals in the water deteriorates the insulation, regardless of the type of insulation employed. In time, the electric power line swells and looses some of its ability to insulate, so that electricity leaks from the power line. In addition rain water often finds its way into the conduit, so that the conduit is wet even above the pool water line. The electricity naturaily follows the path of least resistance to a complete circuit, which may be in the power line or in the pool itself, depending on circumstances such as the amount of electrolytes in the water (that is, salts), temperature, and condition of the brass conduit.
Of course the circuits for such lamps are protected by circuit breakers in the breaker box, and by a ground fault interrupters. In electrically conducting water, such as that found in a swimming pool, however, very little electricity is required to electrocute a person. A current of only about 9 milliamps that passes through a vital portion of a person's body, such as the heart, is required to electrocute a person. According to Underwriters Laboratories, when a person is immersed in conducting water, as little as 15 volts can produce a lethal current of 9 milliamps in a man and a lethal current of 15 milliamps in a woman. Children are even more susceptible to low voltage leakage in swimming pool water.
Building codes universally require that all metal components of a pool or spa, such as the ladders found on the sides of many pools, be grounded, providing a natural path through the water for any electrical current. If a leakage current exists, and a person grasps such a ground, he may be exposed to a danger of electrocution.
Circuit breakers commonly employed in the circuits of swimming pool lights are triggered by much greater current. Thus a swimming pool light circuit may easily leak a lethal current without triggering the circuit breaker. In an effort to overcome this difficulty, ground fault interrupters have been employed. They are set to disconnect the electricity when non-lethal electrical leakage occurs. Such leakage occurs frequently, and may occur intermittently, causing the ground fault interrupter to turn the circuit off frequently. This is an unacceptable nuisance for most pool operators. Many pool operators disconnect the ground fault interrupters.
Consequently, a number of people are electrocuted every year by swimming pool lights. Efforts to eliminate this hazard have not been successful.
To reduce the danger from swimming pool lights, it is customary to install periodically new power lines. This requires draining the pool to a level below the lamp housings. Removing the old power lines from the conduit is often extremely difficult, because typical insulation used in this application swells dramatically when exposed to water, and then fits tightly in the conduit, from which it must be pulled. Changing the lamp, which also requires partially draining the pool, or the power lines is a very involved labor-intensive and expensive job.
Therefore, a need exists for an illumination system for use in a water environment, such as a swimming pool or spa, which eliminates the danger of electrocution, simplifies maintenance and reduces maintenance.